A Brief Synopsis on PET

advertisement
A Brief Synopsis of
PET (Polyethylene terephthalate)
derived from
ethylene glycol
and terephthalic acid
Amorphous PET (APET) has:
• High gloss and excellent toughness
• Excellent gas and good moisture barrier when properly sealed
• Direct food contact approvals
• Used widely for chilled and ambient food and industrial uses.
• Extensively used in deep freeze applications, with caution.
• Par-Pak cannot guarantee the performance of any materials for deep freeze
due to the challenging nature of this process.
• We suggest that all users ensure that the PET packaging used is suitable in
their process without limitation for freezing, sealing, heating and shipping
• PET is the material most commonly recommended and approved by major
retailers.
DPET, is Octal’s
Direct APET material
• Conventionally, PET is pelletized, solid state polymerized and cooled down, then packed for
onward distribution to plastic processors, who would dry the product prior to extrusion.
• With DPET, as part of the copolymerisation process, the melt is NOT cooled, pelletized and
solid stated for onward sale to downstream converters. The polymer melt is directly fed into the
extruder and extruded into sheet. This exhibits all the excellent characteristics of APET without
requiring further drying and extrusion.
• As a result of this process, DPET (as independently assessed on behalf of OCTAL) exhibits a
very good carbon footprint.
rPET is available in one of two formats
• Co-extruded multi-layer sheet referred to as a / b / a food approved blend
The Material composition is:
‘a’ layer of approximately 20% using prime PET resin typically.
‘b’ layer is a mix of up to 50% SUPER CLEAN recycled PET pcw and 30% post
industrial use.
• Mono-layered food approved blend
This is a blend consist of a mix of food approved super clean post-consumer
recycled PET, post-industrial regrinds and prime virgin PET resin.
The postconsumer content is only from reputable sources that have approval for direct
food contact use.
Implication when using post consumer
waste (pcw).
• PCW re-uses PET bottles and other containers from curb side collection programs
and bottle deposit programs.
• Collected material is put through a rigorous sorting, flaking and washing process,
which is then re-extruded into food approved sheet.
• Post consumer recycled material can and will vary in quality and can have a direct
impact down-stream in terms of throughput and quality. As more rPET continues
to be used and re-used, its quality appears to be deteriorating.
• Par-Pak’s current material composition is a mix of high quality industrial waste
generated during the extrusion and thermoforming processes and PCW.
Primary factors that affect the quality and performance of the product during the
thermoforming process are:
 The Intrinsic Viscosity (IV)




Colour variation (tint)
Sheet imperfection, such as gauge fluctuations
Black marks (carbon particles)
Throughput at all levels, primarily at extrusion
The material used by Par-Pak has been developed:
• Within the Par-Pak Group and with our strategic supply partners.
• From reputable UK and European sources of PCW.
• All materials are certificated for direct food contact use.
We have observed with rPET utilizing PCW:
• Good clarity and gloss, as is associated with APET.
• Higher incidence of Carbon particles embedded within the sheet. This is not a
hazard to health, and is generated as a result of the further processing of the
material.
• More likelihood of variations in colour (tint).
• Higher variations of consistency and quality as a result of the PCW content.
• Pricing of rPET is subject to availability of good quality PCW. This is coming under
strain, and is likely to become increasingly difficult to obtain. Availability of bottle
waste is causing concern within the thermoforming industry; major bottle users are
reducing their bottle weights, bottlers are sourcing bottle scrap for use within the
bottling industry, and there is increasing demand for the product
Mono rPET
(with higher amount of post consumer)
We are able to supply material with 100% recycled PCW.
This has significant implication in terms of product quality, and would need to be fully tested.
In particular:
• There may be a visible loss in clarity in the product.
• There may be change in tint (not consistent) within the sheet and product
on a batch to batch basis.
• There may be some imperfections in the performance, quality and
occasional black carbon spots in the sheet.
• The physical properties may not be adequate for some applications due to
lower intrinsic viscosity levels.
• Increased risk of holes in sheet or product.
Download